Simulation Analysis And Experimental Research On Fuel Economy Of Automobile PnG Operating State

The fuel economy of a vehicle is not only affected by the vehicle's own state,but also by road environmental conditions,driver behavior and other factors.In order to verify that good driving behavior can improve the vehicle's fuel economy,the fuel economy study of the pulse-and-glide(PnG)cruising strategy was selected and compared with the traditional constant speed(CS)cruising strategy.Since PnG strategy is a dynamic and cyclic driving mode,it is necessary for the later simulation to establish a vehicle fuel consumption model to obtain accurate dynamic fuel consumption.Based on the fuel consumption test data of the Argonne National Laboratory in the United States,the two transient modeling methods of "two-dimensional interpolation+difference correction" and "polynomial fitting+multiple ratio correction" were used to establish the vehicle's transient fuel consumption model.The verification results of the model show that the transient fuel consumption model has higher fuel consumption prediction accuracy than the traditional steady-state model.Based on the Radau pseudo-spectrum method and the transient fuel consumption model,the traditional fuel vehicles equipped with manual transmission(MT)are taken as the research object,and the optimal gear and minimum fuel consumption are the control objectives.The optimal control problem of PnG cruise strategy is described.And use MATLAB software to solve and analyze the fuel saving mechanism.The results of the solution show that the total fuel consumption of PnG strategy is lower than that of CS strategy,and the average fuel efficiency of PnG strategy is generally higher than that of CS strategy,especially in the middle and low speed range.In order to further compare the fuel saving potential and application prospects of CS strategy and PnG strategy,a new adaptive cruise control(ACC)simulation platform was developed based on Carsim and MATLAB/Simulink.The cruise mode of the original ACC system is only the CS cruise mode.Improve the cruise mode control of the ACC system by adding a PnG cruise mode.Based on particle swarm optimization,the optimal acceleration at each average cruising speed is solved,and the optimal gear is matched by itself.The simulation results show that compared with CS strategy,PnG strategy has a significant fuel saving effect.Finally,through road tests and drum tests,the fuel economy of the PnG strategy was further verified.And the verification results were highly consistent with the simulation results.This shows that the PnG strategy is more fuel-efficient than the traditional CS strategy,and it has good application prospects.